Extjs is one of the most popular libraries to build rich desktop applications. Why ? well, it’s hard to explain, just have a look of what you can do with this library.

Sweet, isn’t it. If you are not impressed notice that all those windows, charts, menu are in a browser. Extjs makes you able to replicate a full desktop experience in a browser container.

The drawback of this is that you code all in javascript, you don’t see any html line at all. If you are comfortable with, you can use Extjs thanks to its dual license: GNU GPL v3 for opensource project and a commercial license if you want to use Extjs in your closed source application. Also the license is per developer seat which means that you can code as much as you want with a single license if you are a freelancer.

I’ve learned to code using Extjs as I always do, trial and error, by examples. Extjs has a huge amount of examples but not all of them have the same code styles and this may lead in having your project  not very well organized. To overcome this, you may want to have a look at Mastering Extjs. I’ve contributed in reviewing this book and I have to admit that the way it teaches how to use Extjs by organic examples and increased difficulty optimizes the time you have to spend to truly understand how a complex framework like Extjs works.  Even if I worked with Extjs from few years I’ve found some techniques and code examples having a better approach instead of the solution I would code without ever reading the book.

The book assumes that you have a basic understanding of the Extjs framework. This basic understanding is very low tho. I can estimate that it takes 1/2 days reading some Extjs examples to have that knowledge. It will focus on having a good code style, multilingual support and a clear unerstanding of the MVC pattern in Extjs. At the end the book will propose ways to optimize the source code and reduce the size of the code that the browser has to download in order to speed up page load and in general app responsiveness/speed.